Apparatus for making screw fasteners



June 30, 1953 L. J. LOVISEK 2,543,401

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June 30,1953 7 L. J. LOVISYEK 2,643,401

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APPARATUS FOR MAKING SCREW FASTENEVRSV.

Filed No v s, 1950 7 Sheets-Sheet 3' "I II III June 30, 1953 L. J.LQVISEK 2,643,401

APFARATUS FOR MAKIN SCREW FASTENERS Filed Nov. 5, 1950 '1 Sheefs-Sheet 4June 30, 1953 L. J. LOVISEK 2,643,401

APPARATUS FOR MAKING SCREW FASTENERS Filed Nov. 5, 1950 '7 Sheets-Shegt5 419 Fras. 4s v FIG. 9.

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June 30, 1953 1. J. LOVISEK 2,643,401

APPARATUS FOR MAKING SCREW FASTENERS Filed Nov. 5, 1950 7 Sheets-Sheet aEMH IIIIIIW w .11 a? 40 ml-um IQIHII Ill 35 66: 7n6? June 30, 1953 J.LOVISEK' 2,643,401

' APPARATUS FOR MAKING SCREW FASTENERS Filed Nov. :5, 1950 Sheets-Sheet7 Patented June 30, 1953 APPARATUS FOR MAKING SCREW FASTENERS Louis J.Lovisek, New York, N. Y., assignor to Parker-Kalon Corporation, NewYork, N. Y., a

corporation of New York Application November 3, 1950, Serial No. 193,965

Claims. (01. 10--2) lhe present invention relates to apparatus formaking screw fasteners, and more particularly to apparatus for formingscrew fasteners from a continuous length of wire stock of a diametersuitable for making screws of a desired size.

I-Ieretofore, a number of separate machines have been required forforming screws from wire stock, namely, one machine for cutting the wireinto blanks of the desired length and forming a head on the blanks,another machine for forming a slot or recess in the screw head, andstill another machine for forming the threads on the shank of the headedscrew blank. Separate skilled operators are usually required for eachseparate machine or operation. Moreover, it was necessary to transferthe screw blanks from one machine to the other between each of the aboveoperations, thereby requiring considerable time and labor in handlingthe partially completed screw blanks, and adding to the cost ofmanufacture.

It is accordingly a primary object of this invention to provideapparatus for performing the steps of at least two of the abovementioned machines on a single machine, thereby effecting a saving of asubstantial portion of the operating expenses, such as the upkeep forseparate machines, and wages for machine operators, and at the sametime, increasing the potential output of finished screw fasteners.

The apparatus for producing screw fasteners according to this inventionperforms the steps of feeding a continuous length of wire stock of adiameter suitable for producing the desired screw size to a cut-offstation, cutting off successive predetermined lengths of the wire stockat said first station to form screw blanks, successively andautomatically transferring the cut-off blanks to a combined heading andthreading station where the heads are formed on the blanks and then thethread is immediately thereafter formed on the shank of the headedblanks without further transfer, and all operations performed by asingle machine.

Another object of the invention is to provide an improved apparatus formaking screw fasteners, characterized by heading screw blanks while theblanks are supported by thread-rolling dies, so that the resultingheaded blanks will be instantly in perfect position for performance ofthe threading operation by the thread-rolling dies.

Other and further objects and advantages of the invention will behereinafter set forth, and the novel features thereof defined by theappended claims.

In the accompanying drawings:

Figure 1 is a top plan of a conventional solid die, double stroke toggleheader as modified to incorporate my invention therein, with a portionof the cover for the drive belts broken away;

Figure 2 is a front elevation of the apparatus of Fig. 1, a portion ofthe cover for the drive belts being broken away in this view also;

Figure 3 is a side elevation of the apparatus as observed from thedriving side;

Figure 4 is an enlarged fragmentary view in rear elevation, as taken onthe line 4-4 of Fi ure 1, showing the cut-off, transfer and threadforming mechanisms;

Figure 5 is a view in vertical section, as taken on the plane of theline 5--5 of Figure 4, showing a headed screw blank positioned in therolling dies preparatory to the rolling of threads thereon;

Figure 6 is a view in horizontal section, as taken on the line 6-6 ofFigure 4; with certain of the parts shown in plan;

Figure 7 is a view in horizontal section, as taken on the line 1-1 ofFigure 4;

Figure 8 is a view in horizontal section, as taken on the line 88 ofFigure 4;

Figure 9 is an enlarged fragmentary detail view of the thread rollingdies which also serve to hold the screw blanks during the headingoperations;

Figure 10 is an enlarged view in side elevation of one of the headedscrew blanks formed by the apparatus of this invention, as it is justprior to the final steps of rolling the threads thereon;

Figure 11 is a view in end elevation of the screw blank of Figure 10;

Figure 12 is an enlarged fragmentary view in perspective of a modifiedform of guide quill, adapted for cutting 01f screw blanks with apyramidal point, for use in making pointed screws;

Figure 13 is an enlarged fragmentary view in perspective of a modifiedform of cut-off knife adapted for cooperation with the quill of Figure12;

Figure 14 is an enlarged fragmentary View in vertical section of thepower transmitting mechanism for the fiddle bow and cut-off knife, astaken on the line I i-14 of Figure 1;

Figure 15 is an enlarged fragmentary view, with certain of the partsbroken away and shown in section, showing the modified quill and cutoffknife of Figures 12 and 13, respectively, in their cooperative positionsat the commencement of a cut-off operation;

Figure 16 is a view similar to Figure 15, show- 3 ing the wire stock asit is initially bent upon further movement of the cut-off knife towardthe quill, preliminary to complete severance of the stock;

Figure 17 is a view similar to Figure 16, showing the wire stock as itreturns to a straightened position upon further movement of the cut-offknife towards the quill, but still without complete severance of thestock;

Figure 18 is a view similar to Figure 17, showing the screw blankcompletely severed from the wire stock upon further movement of thecutofi knife towards the quill;

Figure 18a is a fragmentary view in side elevation, showing the wasteprojections remaining on the end of the wire stock'after the screw blankhas been completely severed, as in Figure 18;

Figure 19 is a view similar to Figure 18, showing the severed screwblank as it is engaged by the transfer finger upon further movement ofthe cut-off knife towards the quill and with the knife in the act ofsevering the jagged ends of the wire stock shown in Figure 18a; I

Figure 20 is a View similar to Figure 19, showing the severed wasteprojections of the wire, being pressed partly into the V-groove of thequill as the knife reaches the end of its blank severing stroke;

Figure 21 is a view similar to Figure 20, showing the cut-off blade onits return stroke ejecting the compressed waste particles from thequill, and further showing the pointed screw blank after it has beentransferred to theheading and thread rolling station in the threadrolling dies, with the blank partly headed and ready for completing thehead and for rolling threads on the shank;

Figure 22 is a top plan of the intermittent transmission mechanism thatoperates the thread rolling dies, the cover plate for the transmissionhousing being removed; and

Figure 23 is a view in vertical section taken on the plane of the line23-43 of Figure 22.

Like reference characters designate corresponding parts'in the severalfigures of the drawings.

In explainingmy invention herein, I have illustrat'ed its application toa conventional header apparatus, known commercially as a solid die,double stroke toggle header, and therefore, only those general featuresof this apparatus have been shown which will assist in a readyunderstanding of the present invention. Reference may be had to priorPatents 1,478,356, 2,160,087 and 2,261,067 for further details orinformation relative to the header structure, but it is to be understoodthat the invention is not limited to headers of this type, since it willbe obvious that it can be applied to so-called crank headers oreccentric-operated headers, as well as to multiple station headerscommercially known as Progressive headers or Duplex headers. Moreover,the number of blows employed in the heading operations is not materialand my invention is not limited to headers of the two'- blow type.

Referring to Figures 1, 2 and 3 of the drawings, I designates the frameof the machine on which is mounted a crankshaft 2 carrying the flywheel3. The toggle mechanism for actuating the heading dies is denotedgenerally at '4. The motor for driving the machine is pivotally mountedas at 5, and is adjustably positioned by means of the adjusting screwand its associated parts generally denoted at -6. Driving con- '4nection between the flywheel 3 and the motor 5 is made by conventionalmeans such as the V- belts 1 and pulley denoted at l, the flywheel, V-belts and motor pulley being enclosed in a cover or guard 8.

Wire stock 9, generally supported on a reel (not shown) at the front ofthe machine, is intermittently fed to the apparatus by means of theintermittent feed mechanism generally denoted at H], the feed mechanismbeing operated by an eccentric II, mounted on the crankshaft 2, throughthe rod 12 and the ratchet and pawl mechanism l3, as will be understoodby those skilled in the art of conventional header machines.

The end of the crankshaft 2 opposite the flywheel 3 carries a crankassembly [4 which is operativ'ely connected with a slide [5 foreffecting reciprocation thereof in a recess [5' (Fig. 14)

in the lateral projection ll of the frame I, this assembly beingpreferably adapted for adjustment, whereby the stroke and dwell of theslide may be varied. The slide 15 is provided with a cam slot [6 foreffecting transverse reciprocal movements of a cut-off knife 39 andfiddle bow, which will be hereinafter more fully described, by means ofa roller l'l' riding in said cam slot. The cut-oifknife and fiddle boware comiected with the roller H by means of the L-shaped member 18.

Actuated'by the toggle mechanism 3 is the conventional punch block orheader die assembly :9 carried by the vertically movable slide 29, inwhich the preliminary c oning and finishing punches or dies are mounted,these punches being designated 28 and. 2 l respectively.

Reference will now be made to the novel combined heading and threadrolling die assembly which has been found to be particularly welladapted for the purpose of making screws in accordance with the methodof this invention. The assembly is generally denoted at 22 and is bestshown in Figures 4 through 8. This assembly 22 provides a cut-off"station 23, and a combined head forming and thread rolling station 24,and includes a block it at the latter station, this block beingvertically extended and received in a vertical recess 21 in the frame Iof the apparatus.

As is best seen in Figures 6 to 8, the vertical recess 27 is slightlyundercut'on one of its sides, as '"seen at 28, and the block 26 isformed to project into and closely fit this undercut side of the recess.The 'block 26 is of a lesser width than the recess Hand is displaceablysecured therein by means of a vertically extended wedge 29 cooperativewith a complementary laterally extended wedge projection 30 on the block28 in an apparent manner, as bestseen in Figure 4.

To accomplish the wire stock cut-off step of this invention, the block26 is provided with a quill 3 1 which is secured against displacement ina bore -32 in'which it is located, by means of a set screw 33. The quill3| has an axial opening 34 therethrough terminating at one "end in abell mouth'35, the opening 34'being in alignment with an opening 36 inthe frame I. The wire stock 9 is intermittently fed from the feedingstation l0 through the openings 36 and 34 until it abuts againsttheadjustable stop 31 which is carriedby a rod '38, the rod 38 beingadjustably across the end of the quill 3| (which end is fiat in the casewhere blunt end screws are to be made) for cutting off the section ofwire stock extending between the end of the quill and the stop 3?. Thecut-off knife 39 is carried at the free end of a bar 4!] and isconnected thereto by means of the bolt 4!, relative movement between theknife '39 and the bar 40 being prevented by the undercut joint denotedat 42. The opposite end of the bar fit is connected to the member I9 ofthe operating mechanism, as best seen in Figure i l at 43. Intermediateits ends, the bar 40 is slidably supported on the frame I by means ofthe guide block 44 which is suitably secured to the frame 5. Thus, it isreadily apparent that operation of the slide 15 effects timedreciprocation of the cut-off knife 39 across the face of the quill 3i,thereby cutting off screw blank sections from the wire stock 9.

The apparatus which efiects the screw blank transfer step of the presentinvention, comprises a fiddle bow t5 connected at one of its ends, as atit, to the motion transmitting member I6, the free end of the fiddle bow45 terminating in a yoke d5. Pivotally mounted in the yoke 46, by meansof the bolt 57, is a transfer finger-carrying-block d8, this block 48having an opening 48 therethrough at a slight angle relative to thevertical for receiving the transfer finger 49 which is adapted forvertical adjustment in the opening ts by means of the set screw and jambnut assembly 56. A pair of studs 5! and 52 are carried at the lower sideof the fiddle bow 45 and block d5, respectively, and a tension spring 53interconnects the studs EI and 52 so as to bias the transfer finger d9to the left, as seen in Figure 4, or towards the cut-off knife, aboutthe pivot bolt ll, into abutting contact with the stop member 5 i whichis mounted on the guide block 44, as at The operation of this transfermechanism will be hereinafter more fully described.

Passing now to the heading and thread rolling station 54% of thisinvention, there is located at this station a second verticallyreciprocable slide block 56 which is slidably carried in the sta tionaryblock 26 and is restrained from displacement relative thereto by theoff-set rib 5'! on the block 56, slidingly engaging behind thecorresponding under-cut of the block 26, and behind the verticalretainer plate 58 which is secured to the outside face of the block 26by means of a series of bolts as at 59. The vertically slidable block isalso held against transverse play and axial misalignment by means of anadjustable wedge or hearing 6% mounted between the inclined wall iii ofthe block 26 and the wall 62 of the block .6, best seen in Figures 6 to8. This wedge shaped bearing is adjustably positioned by means of thescrews 63 in an obvious manner. I

Carried by the slide block 56 as at 64 and by the stationary block as at64 are, respectively, a reciprocable threading die and a stationarythreading die, the reciprocable die 64 being adapted for movementlengthwise of and across the fixed die 6 with the adjacent faces of thedies spaced to properly accommodate a screw blank therebetween that isto be threaded, as in conventional thread rolling machines. For furtherdetails of the thread rolling operation, reference may be had to PatentNo. 2,165,007. These thread rolling dies 64 and 64' are removablyclamped in corresponding recesses in the slide block 5s and thestationary block 26 by means of screw clamps 65 and 65 and screwfastened wedges 66 and 66'.

The thread rolling dies 64-64 act additionally as heading die segmentsduring the heading operation, and a second pair of heading die segmentsor blocks 61-61, disposed adjacent the threading dies, complete a cavity68 into which the screw blank 69 (see Figure 5) is driven by the coningpunch 20 when each severed screw blank is transferred into register withthe cavity 66 by means of the transfer mechanism previously described.The heading die segment 6'! is mounted in a recess in the slide block 56by means of a pair of bolts 61", and the segment 61' is likewise mountedin the stationary block 26. The cavity 68 is formed by the arcuaterecesses in each of the adjacent corners of the threading dies 64-64 andthe heading die segments 61--6|', as best seen in Figure 9.

Intermittent reciprocation of the slide block 56 and consequent rollingof threads on the screw blanks 69 which are successively positionedtherein is preferably effected by means of a transmission unit 16 whichis driven by means of a chain or the like 7| operatively interconnectingthe shaft 2 and the transmission drive sprocket 72 which is keyed on theinput shaft 73. Rotation is thus transmitted through the segment gear'54, thence to the gear '15, which completes a revolution uponapproximately a revolution of the gear 14 and dwells for the remainingrevolution of said gear '14. A second gear 15 is mounted on the shaft 16with gear 15 and is in driving contact with a 2 to 1 reduction gear 17keyed to shaft 18. Thus, it is apparent that each complete revolution ofthe crankshaft 2 will cause a complete revolution of the shaft 18, thefull revolution of shaft 78 occurring during the A of a revolution ofshaft 13 and crankshaft 2. Other mechanisms may be employed, if desired,to obtain the intermittent motion above referred to, in lieu of theintermittent gear transmission disclosed herein.

Keyed to shaft '18 is a crank arm 19 which is adjustably interconnectedwith the bottom end of the vertically reciprocable slide block 56 bymeans of a longitudinally adjustable pitman 86. The length of the pitman86 determines the extent of upward movement of the block 56, andtherefore, the size of the cavity 68 at the heading station 24 may beslightly varied to accommodate screw blanks of slightly differentdiameters. The block 5% is provided with a spring loaded bumper S! tocushion the blow of the slide block 56 against a cap plate 32 when theblock 55 reaches its uppermost limit of travel (see Figures 4 and 5).The cap plate 82 is also provided with an adjustable stop screw 83 whichis adapted to make fine adjustments to the size of the cavity 65, suchas adjustments on the order of approximately .001" or less. The stopscrew 83 acts to force the crank arm is slightly off center due to theinherent slight back-lash in the intermittent gear mechanism'of thetransmission 10.

The formation of screw threaded fasteners by the novel apparatushereinbefore described will now be summarized.

A continuous length of wire stock of appropriate size for the screwdesired is supported on a reel (not shown) and is intermittently fed bythe feeding mechanism 19 through the quill 31 until it abuts against theadjustable stop 31 at the cut-off station 23. Then, in timed sequence,the cut-off knife 36 and the fiddle bow 45 are moved in unison to theright, as viewed in Figure 4, the free end of the knife being providedwith an arcuate recess 33 toengage the wire stock and cut off a screwblank. Movement of the fiddle bow to the right in Figure 4 shifts theblock 43 likewise to the right and permits the block to swing downwardlyuntil the lower portion of the transfer finger 49 engages the cut offblank and firmly holds the blank in the recess 39 of the cut-off knife39. I Continued movement of the cutoff knife 39 along with the transferfinger #89 carries the screw blank to the heading station 2t, until itis registered with the cavity 68 defined by the segments of the threadrolling dies G l-4 and the coacting segments 61-61. The machine is sosynchronized that the preliminary or conino punch 20 now strikes thescrew blank, driving it into the cavity 68 and up against the stop pinand partially forming a head on the blank, as seen at 69 in Figure 5.The coning punch 23 then moves back and the head finishing punch 2| isautomatically shifted into position for movement against the head of theblank 69, thereby completing the heading operation while the blank isheld between the thread rolling dies. If desired, the heading punchesmay include means for striking a slot, socket or other recess in thehead of the blank during the heading operation.

Responsive to the force of the punches 2D and 2!, a portion of the metalof the screw blank shank is forced into the grooves between thethreading ribs on the faces of the threading dies t-S, thereby forming aline of projections 82 on diametrically opposite sides of the screwblank 39, as best seen in Figures and 11. These projections 82 are smallsegments of the thread which is to be rolled on the shank and act topositively and accurately locate the blank between the thread rollingdies 64-64 preparatory to the thread rolling step.

The machine is 'so-timed that during the foregoing operation, theintermittent transmission 7;: has been in its dwell period during thecutoff and blank heading operations, but thereafter the segmental gear14 now engages gear 15, as inFigure 23, and the sha'ft'l8 is caused tocomplete one cycle or revolution, as has been hereinbefore described.Accordingly, during this cycle, the pitman 811 pulls the slide block 56down, thereby rolling the threads on the shank of the screw blanktbetween the thread rolling dies. As the blank 69 passes the lower end ofhe die it falls into the chute 84, and thence into a suitable receiveror'handling reccptacle (not shown). During this thread rollingoperation, the cut-off knife 39 and transfer finger as have moved backinto their original positions, and another section of the wire stock hasbeen fed in,.cut off, and transferred to the heading station, and isready to be driven, by the coning punch'zfl, into cavity 58.

The above described method and apparatus forms a screw having asubstantially flat or blunt leading end, but pointed screws may be madeequally as well by merely a slight modification of some of the parts, aswill now be described.

Figure 12 shows a modified quill 85 adapted for cutting screw blankswith'a pointed leading end. This quill is the same as the quill 3|except that its rear end face 85 is provided-With aprojection 3! on theside nearest the heading station, the projection having a pair ofangulariy disposed-cutting edgesBB and a corresponding V-shapedrecess orgroove 89 extending therethrough radially of the quill 85.

The cut-oir' knife vi9ll,'shown in Figure 13, is adapted-tocooperate'with the cutting edges 88 of the modified quill by theprovision of a V-shaped projection 9| which iscomplementary to theV-shaped recess 89 in the quill 85. The knife 93 is further providedwith a cutting edge 92 for a purpose which will hereinafter becomeapparent.

The operation of the modified form of the quill 85 and the knife 99 willnow be described with reference to Figures 15 through 21, it beingunderstood that the machine operates in the same manner as hereinbeforedescribed.

As shown in Figure 15, the wire stock 9 has been fed up to the stop 31,and the cut-off knife 9i: is moving to the right into engagement withthe screw blank section 59. Further movement of the knife 98 bends theend 69 of the wire stock over, as in Figure 16, forming a flat face 93on the left side of the blank 69, and continued movement of the knifestraightens the wire again, as in Figure 17. Still further movement ofthe knife iii] causes the V-shaped projection 9| thereon to push theblank past the cutting d es 88 on the projection 8? of the quill, and atthe same time flattening the righthand face of the blank by the naturalmaterial flow induced by forcing the blank against a cutting edge of thequill, thereby completing a point on the end of the blank 69, and thetransfer finger 49 has started to swing down into blank-engagingposition.

Cutting of the pointed blank 69 has left a pair of small waste bits $4on the end of the wire stock 9 (see Figure 18a), which must be removedto produce a clean end on the wire for the next succeeding blank to becut off.

As seen in Figure 19, the transfer finger has now engaged the severedblank 69 which is now being transferred to the heading station, and thecutting edge of the knife dB is ready to cut off the waste bits 53%.Further movement of the knife, as in Figure 20, severs the bits Q4 andcom-.

presses them against the projection 8?, thereby spreading a portion ofthese bits into the V-shaped recess or groove 539.

In Figure 21, the blank 69 has been punched into the cavity 58, and thecut-off knife and the transfer finger 4d are on their return stroke.During this return stroke the rear edge of the V-shaped projection 9iwill eject the cut off bits of waste from the V-grcove 89, causing saidbits to drop from the quill.

The pointed end of the blank that is formed at the above describedcut-off station is substantially pyramidal in form, but the point isfurther shaped'by the rolling die 64" and the heading die segment 61"into a round, tapering point. The thread rolling dieii a" and theheading die segment are slightly modified for purposes of threading apointed screw, as seen in Figure 21, by being inclined toward each otheron their inner faces, as atQE, to form and thread the desired point. Informing pointed screws as above, the stop member 51 is not used.

Interrupted threads and other shapes and types of screws may be producedaccording to the invention hereinbefore described by appropriatelychanging the machine tools, such as the dies.

While the specific details have been herein shown and described, myinvention is not confined thereto as changes and alterations may be madewithout departing from the spirit thereof as defined by the appendedclaims.

.I claim:

1. Apparatus for making screw fasteners, comprising means for feeding acontinuous length of 9 wire stock to a cut-off station, means at saidoutofl station for successively cutting off predetermined lengths of thewire stock to form screw blanks, means for transferring the cut offscrew blanks from the cut-off station to a second station, a pluralityof relatively shiftable die segments at said second station, said diesegments defining a screw blank-receiving cavity, means at said secondstation for driving, the, screw blank into said cavity for forming ahead on the screw blank, at least two of said die segments havingopposed longitudinally extended screw blankengaging faces provided withthread-rolling ribs and grooves, and means operative in timed relationto the screw blankdriving means aforesaid for relatively shifting saidlast-mentioned die segments to form threads on the screw blank after thescrew blank has been headed.

2. Apparatus for making screw fasteners as defined in claim 1, whereinthe means at the cutoiT station for successively cutting offpredetermined lengths of .wire stock, includes a quill having aprojection on its cut-off end disposed at one side of the central axisof said quill, said projection being provided with a V-shaped groove,and a cut-on knife having a V-shaped rib cooperative with theV-shapedgroove aforesaid for successively cutting off pointed screwblanks from the wire stock, said die segments each being formed with anarcuate depression having a tapered end, and the depressions togetherforming a pointed screw blank-receiving cavity.

3. Apparatus for making screw fasteners, comprising means for feeding acontinuous length of wire stock to a cut-off station, means at saidoutoff station for successively cutting off predetermined lengths of thewire stock to form screw blanks, means for transferring the out offscrew blanks from the cut-oft" station to a second station, means atsaid second station for forming a head on the screw blank, and meansalso at the second station for forming threads on the screw blank, saidmeans at the cut-off station for successively cutting off predeterminedlengths of wire stock including a quill and a cut-ofi knife, said quilland cut-01f knife respectively having a V-shaped groove and acorresponding V-shaped rib cooperative with each other for successivelycutting off point screw blanks and leaving waste bits remaining on eachsucceeding section of wire stock to be cut OH, and means also on thecut-off knife aforesaid for cutting off and ejecting said waste bits.

4. Apparatus for making screw fasteners, comprising means for feeding acontinuous length of wire stock to a cut-ofi station, means at saidcutofi station for successively cutting off predetermined lengths of thewire stock to form screw blanks, means for transferring the cut offscrew blanks from the cut-off station to a second station, means at saidsecond station for forming a head on the screw blank, and means also atthe second station for forming threads on the screw blank, said secondstation including a combined heading and thread-rolling die assembly,and a two-blow, toggle operated heading punch mechanism cooperative withthe die assembly aforesaid.

5. Apparatus for making screw fasteners, comprising means for feeding acontinuous length of wire stock to a cut-01f station, means at saidcutoil station for successively cutting off predetermined lengths of thewire stock to form screw blanks, means for transferring the cut offscrew blanks from the cut-off station to a second station, means at saidsecond station for forming a head on the screw blank, and means also atthe second station for forming threads on the screw blank, said secondstation including a stationary thread-rolling die and a reciprocablethreadrolling die cooperative with said stationary die for formingthreads on each successive screw blank, a two-blow, toggle-operatedheading mechanism, and means for holding each successive screw blankduring the operation of said heading means.

6. Apparatus for making screw fasteners, comprising means for feeding acontinuous length of wire stock to a cut-off station, means at saidoutoff station for successively cutting off predetermined lengths of thewire stock to form screw blanks, means for transferringthe cut oil screwblanks from the cut-off station to a second stablank, and also includinga stationaryheading die segment and a reciprocable heading die segment,the thread-rolling dies and heading die segments aforesaid cooperatingwith each other to provide means for holding each successive screw blanktherebetween during the heading operation and in starting position inthe threadrolling dies for the thread-rolling operation.

'7. Apparatus for making screw fasteners, comprising means for feeding acontinuous length of wire stock to a cut-off station, means at said out-01f station for successively cutting off predetermined lengths of thewire stock to form screw blanks, means for transferring the out 01fscrew blanks from the cut-01f station to a second station, means at saidsecond station for forming a head on the screw blank, and means also atthe second station for forming threads on the screw blank, said meansfor forming screw threads on the screw blank including relativelyreciprocable thread-rolling dies operable in timed relation to thecut-off means at the cut-off station, said thread-rolling dies defininga screw blank receiving cavity in one position, into which cavity thescrew blank is transferred from the cut-off station and held stationaryduring the heading operation at the second station preliminary to thethread-rolling operation performed by the thread-rolling dies.

8. Apparatus for making screw fasteners, com prising means for feeding acontinuous length of wire stock to a cut-off station, means at saidoutofi station for successively cutting off predetermined lengths of thewire stock to form screw blanks, means for transferring the out offscrew blanks from the cut-ofi station to a second station, means at saidsecond station for forming a head on the screw blank, and means also atthe second station for forming threads on the screw blank, said meansfor forming screw threads on the screw blank including relativelyreciprocable thread-rolling dies operable in timed relation to thecut-off means at the cut-off station, said thread-rolling dies defininga screw blank receiving cavity in one position, into which cavity thescrew blank is transferred from the cut-off sta tion and held stationaryduring the heading operation at the second station preliminary to thethread-rolling operation performed by the threadrolling dies, and saidheading means at the second station including a two-blow, toggle-oper-11 ated header mechanism operable in timed relation to the cut-oif meansand to the thread rolling dies.

9. Apparatus for making screw fasteners, com prising means for feeding acontinuous length of wire stock to a cut-off station, means at saidoutoff station for successively cutting oiT predetermined lengths of thewire stock to form screw blanks, means for transferring the cut offscrew blanks from the cut-off station to a second station, a combinedheading and thread-rolling die assembly at said second station, said dieassembly including a pair of relatively shiftable threadrolling dieshaving opposed longitudinally extended screw blank-engaging facesprovided with thread-rolling ribs and grooves, and a reciprocableheading punch mechanism also at said second station and cooperative withthe die assembly aforesaid to form a head on said screw blank.

10. Apparatus for making screw fasteners as defined in claim 9, whereinsaid die assembly includes a pair of relatively shiftable supports, athread-rolling die carried by one of said supports and a complementalthread-rolling die carried by the other support, a heading die carriedby one of said supports and a complemental heading die carried by theother support, each of said dies having an arcuate depression therein,said depressions defining a cavity between said dies when the supportsare in one position relative to each other, said heading punch mechanismhaving means for shifting the punch toward said die assembly when thesupports are in said one position to drive the screw blank into saidcavity and head the same, and said die assembly also including meansoperative in timed relation to said punch mechanism for relativelyshifting said supports to roll threads on the headed screw blank.

LOUIS J. LOVISEK.

References Cited in the file of this patent UNITED STATES PATENTS

